Our final excerpt from Aristocrats Of The Garden by E. H. Wilson deals with Lilacs which seem to be considered “old-fashioned” plants today; perhaps their size and limited spring blooming season is to blame. Nonetheless, if you’ve got room, Lilacs can make a beautiful contribution to the spring garden.
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ARISTOCRATS OF THE GARDEN
ERNEST H. WILSON, 1917
The most adaptable group of flowering shrubs for floral use
Lilacs are among the few hardy shrubs that have truly entered into their kingdom in the gardens of eastern North America. They need no introduction to readers and well they merit their popularity. For regions where cold winters are followed by hot, dry summers they are ideal shrubs. The Common Lilac (Syringa vulgaris) is the most accommodating of plants and thrives in all sorts of queer places and under all sorts of adverse conditions, but its progeny and its congeners are more exacting, and if good results are expected the plants must be treated liberally.
Now, the Common Lilac is native of the mountains of Bulgaria and was sent from Constantinople to Vienna about 1560. From there it soon reached western Europe and both purple and white kinds were cultivated in London in 1597, by Gerard. It is not known with certainty when, or by whom, this Lilac was introduced to North America, but Washington wrote about it in his diary and planted it at Mt. Vernon where his plants or their descendants are growing to this day. But although so long cultivated in gardens it is only recently that its native habitat has become known. In the Arnold Arboretum may be seen growing specimens raised from seeds gathered from wild plants. They have narrow clusters of dull-purplish flowers and are by no means attractive garden shrubs.
During the last fifty years horticulturists, especially those of France and in a lesser degree those of Germany, have paid great attention to the Common Lilac and the result has been a plethora of beautiful shrubs. In fact, virtually all the plants known in a general way as Lilacs have been derived from S. vulgaris. I shall recur to this point later, but it may be stated here that the possibilities of improving upon the present-day forms of the Common Lilac appear to be few but there are other members of the kingdom possessing vast potential values.
The Lilacs, of which some twenty-five species are known, are all native of the Old World and some are shrubs and others small trees. The Common Lilac (S. vulgaris) and its Hungarian confrere (S. Josikaea) ire native of southeastern Europe; the Persian Lilac grows wild in southwestern Asia from the Caucasus to Afghanistan, and in the western Himalayas S. emodi is found. All other known species are natives of eastern Asia and no fewer than seventeen species are indigeneous in China proper. Only one species (S. japonica), and that a Tree Lilac, is found in Japan. In the gardens of Peking and of other places in northern China the white-flowered S. affinis has been cultivated from time immemorial.
All Lilacs are very hardy plants, and, notwithstanding, the fact that none is native of this country every species so far brought into cultivation has proved hardy in the Arnold Arboretum. When their wide range of distribution is duly considered this is remarkable. In very severe winters the Himalayan S. emodi suffers somewhat and the flowers of the Chinese S. oblata are occasionally injured by late spring frosts but no other sort is hurt. And not only are Lilacs quite hardy in the colder parts of New England and elsewhere but they thrive better there than they do across the water in Great Britain.
As mentioned already the ordinary colored and white forms of the Common Lilac will withstand considerable hardship and abuse but their progeny to give the best results demand a good soil and this is true for all the other species. A well-drained, good, rich loamy soil suits them best and if the soil contains a certain amount of lime so much the better, for Lilacs generally are fond of lime. Full exposure to the sun and air is necessary and their beauty is displayed to best advantage when the plants are allowed a sufficiency of space in which to develop freely. They are essentially plants for northern New Eng- land and regions with a similar climate; in southern New England and southward the leaves in summer are often temporarily disfigured by mildew.
A decade or a little more ago it was customary to propagate Lilacs by grafting them on Privet (Ligustrum) stock, but this pernicious practice has met with the opprobrium it merits and today any dealer selling plants so propagated deserves to be ostracized. It is the nature of most Lilacs, and of the Common Lilac in particular, to sucker freely and this alone demonstrates the necessity for their being on their own roots. If the plants get unshapely or too large, own-root Lilacs may be cut almost to the ground with advantage for they will spring up and soon make shapely bushes again. Cuttings three to four inches long of green wood taken in early June, or of thin but firm, half-ripened wood taken from mid-July to early August, and inserted in prepared soil or sand on a spent hotbed, or in pure sand in a frame and kept close, will root in about six weeks, and in three years make nice plants. Also they may be budded or grafted on seedling stock of the Common Lilac and by this method, although it is not to be recommended, salable plants are produced in two years. When potting the stocks carefully remove all adventitious buds; suckers should not be used as stock since it is impossible in these to control the development of adventitious buds. But, after all, there is no valid reason for propagating Lilacs other than by cuttings for by this means the particular variety is on its own roots and the advantage to the garden lover is obvious and lasting.
In the Arnold Arboretum about one hundred and twenty named varieties of the Common Lilac are cultivated and in addition some twenty species and several hybrids, and the season of flowering lasts from about the first of May to the first week of July. In Highland Park, Rochester, N. Y., where great attention has been given to these plants, there is the most complete collection of the varieties of the Common Lilac to be found anywhere on this continent. In all, this park has two hundred and ninety-seven kinds of Lilacs and on May 22, 1915 – “Lilac Sunday” – between the hours of six A. M. and eight P. M. some fifty to sixty thousand people visited this collection.
Such collections are of great interest and of much educational value; but private gardens cannot accommodate such numbers.
If the best only be desired no such quantity is necessary, for within the limits of a dozen the best and most desirable kinds of the Common Lilac may be had. In recent years many of the seedlings raised and named and sold by nurserymen show no improvement on the older varieties. The beauty limit appears to have been reached and it is evident that no great additional improvement can now be expected from seedlings of the Common Lilac. But granted that a dozen will include all that is best in these plants the selection is onerous and difficult since individual taste is all important. Some people do not like the double-flowered sorts and others have preferences for certain shades of color. I am without prejudice or bias in these matters and of the sorts of the Common Lilac of proven merit in the Arnold Arboretum I would select the following dozen: Marie Legraye, Princess Alexandre (single white) ; Madame Lemoine, Miss Ellen Willmott (double white) ; Gloire de Moulins, Macrostachya (pink); Charles X (rosy lilac); Volcan, Congo, Philemon, Ludwig Spath (dark red- purple); Justi (blue). Be it understood all these are forms of the Common Lilac and it is not supposed that this selection in its entirety would satisfy every enthusiast.
But the Common Lilac and its very numerous descendants do not exhaust Lilacdom. Far from it – very far from it. There are other species and there are hybrids of singular beauty and charm which deserve wide recognition. Some blossom earlier than the Common Lilac and its forms, and others later; together they extend very considerably the Lilac season. Further, it is in the hybridizing of these species that advance in this useful and pleasing class of plants must be looked for in the future. As we shall see later a beginning has been made and our gardens enriched thereby.
Each succeeding year in the Arnold Arboretum there is a close race between two Chinese species (S. affinis and S. oblata), to be the first Lilac to blossom and usually the first-named wins. This has white flowers and is very abundantly cultivated in the gardens of Peking, and from there was introduced into the Arnold Arboretum by Mr. S. T. Williams in April, 1904. It is a tall bush of loose, irregular habit and has thin branches and sweetly fragrant flowers. The wild prototype of this Lilac was recently discovered in northern China and named var. Giraldii, after Pere G. Girald, an Italian priest of the Roman Catholic Church, and reached us through V. Lemoine et Fils in 1906. This has mauve-colored flowers which open about the same time as the type. The other species (S. oblata) is a sturdy and broad shrub of good habit and has handsome leaves, thick and leathery in texture, which in the autumn turn to a deep, bronze-red or wine color. The flowers are large, pale lilac, and very fragrant but unfortunately they are often injured by late frosts. It was introduced into England by Robert Fortune from Shanghai about 1854. In Peking gardens it is much cultivated and Dr. E. Bretschneider sent seeds from Peking to the Botanical Garden, Petrograd, where plants from this source flowered in 1888.
The next Lilac to open is S. pubescens, also native of northern China, and was introduced in 1882 by Dr. E. Bretschneider who sent seeds to the Arnold Arboretum, where it flowered for the first time in 1886. This is a free-growing and free-flowering shrub with erect and rather slender stems, small hairy leaves, and large clusters of pale lilac, fragrant, long-tubed, and rather small flowers with dark violet anthers and is among the most beautiful of all Lilacs. These three Chinese species are the heralds of Lilacdom. In rapid succession follow the Common Lilac with its numerous progeny and several other species.
After the Common Lilac has finished flowering, or nearly so, the Persian Lilac (S. persica), with its huge clusters of small fragrant flowers which weigh down the slender branches, assumes the throne. This lovely Lilac was cultivated in England as early as the middle of the seventeenth century but it is now all too seldom seen in gardens. In cultivation it is a broad and shapely bush of medium height with small leaves and is extraordinarily floriferous. The type has pale rosy purple flowers, and so, too, has the form laciniata with deeply incised leaves, but there is also a white-flowered variety (alba).
Closely related to the Persian Lilac is S. pinnatifolia, a new-comer which I had the pleasure of discovering on the borders of China and Thibet and of introducing to cultivation in 1904. This species is remarkable in having pinnately divided leaves and in this character is distinct from all others. It has small pale mauve-colored flowers which are borne in broad pyramidate clusters; but thus far, under cultivation, it has not flowered freely and unless it improves with age it will have to be considered more in the light of a curiosity than anything else.
The most distinct of all Lilacs is the new S. reflexa with narrow, cylindrical flower clusters from nine to twelve inches long which arch downward from near the base and thus hang somewhat like the inflorescence of the Wistaria. The expanding flower-buds are bright red and the open flowers are pale rose color. It will thus be seen that this is a plant of singular and most distinctive beauty and in the hands of the hybridist may be the forerunner of a race totally different in aspect when in flower from present-day Lilacs. A strong-growing shrub from eight to twelve feet high, with erect stems and oblong lance-shaped leaves, its season of flowering is mid- June. It is native of the margins of woods and thickets on the mountains of western Hupeh, in central China, where I had the good fortune to discover it in 1901, and of introducing it, together with another new species
(S. Julianae), in 1902. The latter is a broad shrub scarcely exceeding five feet in height but is twice that much in diameter, and has thin and twiggy branches and small, softly hairy leaves. Its rather small clusters are very freely produced and the flowers are small and fragrant and have violet-colored anthers. It differs from all other Lilacs in having the stalks of the inflorescence and of the individual flowers and also the outer surface of the corolla-tube a deep purple color. The inner surface of the corolla is white so that as the flowers open the inflorescence is purple and white and the contrast is most pleasing and is heightened by the dark violet anthers. It flowers toward the end of June.
A late-flowering species which under cultivation has yet to show its qualities in perfection is S. tomentella. I saw this plant in flower for the first time on July 9, 1908, on the frontiers of eastern Thibet at an altitude of nine thousand feet, and I thought then that I had never before seen such a handsome species of Lilac. It had foot-high, broad panicles of pink to rosy lilac colored flowers and on other bushes they were white. The plants were from eight to fifteen feet high, much-branched yet compact in habit, and the wealth of flower clusters made it conspicuous from afar. The leaves are elliptic-lance-shaped or rather broader, from four to six inches long and more or less hairy on the underside. In 1903, I had collected in the same locality seeds of this Lilac and successfully introduced it to cultivation. Being rather variable in certain characters it has received several names (S. Wilsonii, S. Rehderiana, S. alborosea), but it must be known by its oldest name of S. tomentella. Under cultivation it has flowered several times and I am patiently waiting for it to show its real character.
Of the late-flowering Lilacs the best known in this country and perhaps the hardiest of all is S. villosa, a native of northern China; and from near Peking, introduced by Dr. E. Bretschneider into the Arnold Arboretum in 1882. It is a large shrub of excellent habit with erect fairly stout branches and oblong-lance-shaped, rather pale green leaves. The flowers are rose-colored, pink, or nearly white, but they have an unpleasant odor. It is, however, a first-rate garden shrub, exceedingly floriferous, and very valuable for its hardiness and for its late flowers. Very similar in habit to the above but with bluish purple flowers is the Hungarian Lilac (S. Josikaea) and though much inferior to its Chinese relative as a garden shrub it has proved valuable as a parent as we shall see when we come to the hybrids.
Of all late-flowering Lilacs the most strikingly handsome is S. Wolfii, native of Mandshuria and introduced into cultivation at Petrograd by Russian botanists. From there it was sent to the Arnold Arboretum in 1906, before it had received a name. In foliage and habit it resembles S. villosa but it is much more vigorous and a taller plant. The flowers are small, dark blue-purple to rose-purple and are borne in erect, branched clusters often two feet high and a foot broad and are produced in great profusion. Unfortunately the flowers lack the fragrance of the Common Lilac and of several of the Chinese species but in spectacular beauty it transcends them all.
The Himalayan Lilac (S. emodi) is among the last of the true Lilacs to flower and is less hardy than any other. It is a large bush, or bushy tree, occasionally eighteen feet tall, with oblong, pointed leaves, light yellow-green above, silvery gray, and hairy below, and bears long, narrow clusters of small white fragrant flowers. In its pale foliage it is distinct from other Lilacs and it is one of the very few species which thrive better in Great Britain than in New England.
In 1915, the last of the true Lilacs to flower in the Arnold Arboretum was S. Sweginzowii, a new-comer from northwestern China. This is a shrub of compact habit with rather slender dark red branches and twiggy branchlets with dark dull green sharp-pointed leaves and long narrow clusters of delicately fragrant blossoms. The flowers are flesh-colored in bud and nearly white when fully open and the corolla-tube is slender and about half an inch long.
Of true Lilacs some half-dozen other species are in cultivation in the Arnold Arboretum and promise to have their own peculiar sphere of usefulness in gardens. But at present we do not know enough about their garden value, and, since they are scarcely obtainable, further mention of them may be omitted.
The Tree Lilacs, of which there are three species all native of northeastern Asia, differ from the true Lilacs in having a short corolla-tube and protruded stamens. They are large shrubs or small trees with large, broad, much-branched clusters of white flowers of unpleasant odor. They blossom when the flowers of the latest of the true Lilacs are fading. The first of these Tree Lilacs to bloom is S. amurensis, from the Amur region of northeastern Asia. This is a small bushy tree with dark green leaves and flat- spreading and slightly drooping clusters of ivory- white flowers. The next to open its flowers is S. pekinensis, native as its name suggests of northern China, and is a large bush or bushy tree from twenty-five to thirty feet high and as much through the crown. The branches are more or less pendent at the ends and are clothed with lustrous reddish brown bark which separates into thin layers like that of certain Birch trees. The pointed leaves are long and narrow and hang gracefully and are surmounted by half-drooping flower clusters which are flat and un-symmetrical and smaller than those of the other two species of this group. It was introduced into cultivation by Dr. E. Bretschneider who in 1882 sent seeds to the Arnold Arboretum, where it flowered for the first time in 1889.
The last to flower is S. japonica and this is the best known of the Tree Lilacs. It is common in the moist woods and forests of central Japan and increasingly so northward and throughout Hokkaido, whence it was introduced into cultivation by Mr. William S. Clark who sent seeds to the Arnold Arboretum in 1876. At its best it is a round-topped tree from thirty to forty feet tall with a clean, stout trunk covered with smooth, lustrous bark like that of a Cherry tree. The leaves are large, thick, and dark green and the flowers are borne in large, erect symmetrical clusters. The wood is very durable in the ground and for this reason is esteemed above that of all other trees by the Ainu people of Hokkaido for making their inaos or wooden wands used for religious and ceremonial purposes. These inaos are looked upon as continual guardians against harm from Nature, disease, and evil spirits.
Apart from the very numerous seedling varieties of the Common Lilac there are a number of very beautiful Lilacs of hybrid origin and in the years to come a great development of this favorite shrub may be looked for along these lines. Hybrids are usually more vigorous in growth than species and often vastly more useful as garden plants. Plant-breeding is full of surprises and it is often the case that parents of indifferent or relatively little garden beauty by judicious mating yield offspring of inestimable value. Already this has happened in Lilacdom. The Hungarian S. Josikaea is perhaps the least beautiful of all known Lilacs but crossed with the Chinese S. villosa it has given rise to a handsome new race known collectively as S. Henryi after the originator, Monsieur L. Henry, a gardener at one time attached to the Jardin des Plantes in Paris. The best known and most beautiful of these hybrids is Lutece, which is a compact, fast-growing, large shrub with foliage resembling that of S. villosa, and large, erect clusters of rose-purple flowers and it is one of the latest of all Lilacs to blossom.
The oldest of Hybrid Lilacs and one of the brightest jewels in the crown of Lilacdom is the Rouen Lilac which appeared in the Botanic Garden at Rouen in 1795. It is a hybrid between the Common Lilac (S. vulgaris) and the Persian (S. persica) but through an error as to its origin it was christened S. chinensis a name at once unfortunate and utterly misleading. In gardens it is also known as S. rothomagensis. It is one of the most floriferous of all Lilacs and in its slender branches and narrow leaves and its small flowers borne in enormous clusters it resembles its Persian parent while the color of the flowers shows the influence of the Common Lilac. In addition to the type there is a form (alba) with nearly white flowers.
Another interesting hybrid, also raised in France, is S. hyacinthiflora which is a cross between the Common Lilac (S. vulgaris) and the Chinese S. oblata. It is a large and vigorous and shapely plant with good foliage and small clusters of small, semi-double, bluish purple, very fragrant flowers. It is less ornamental than many other Lilacs and as a garden plant it is chiefly valuable on account of its earliness to blossom, a character which it inherits from its Chinese parent.
There are other hybrids of value though less well known, but enough has been written here to prove, if it be necessary, that even if the Lilac has entered into its kingdom the frontiers of its dominion have not yet been approached.